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The cold desert ecosystem of the north-western Himalaya in India's is considered to be the most vulnerable region to climate change. In this region, Juniperus macropoda Boisser grows across an altitudinal gradient and is highly sensitive to biotic, physiographic, and climatic factors. Keeping this in view, the present study aimed at ascertaining the response of Juniperus macropoda to changing climatic conditions. To achieve the target of the study, the area (elevation ranges from 3525 to 4150 m asl) was divided into thirteen elevation ranges in the cold desert of Lahaul valley (Himachal Pradesh). The NDVI change detection map from 1994–2017 revealed an increase in the area under the vegetation in the NDVI range of 0–0.15 (240%) and 0.15–0.30 (32%), which indicated the emergence of grasses and new recruits in the area. An increase in the minimum and maximum temperature during monsoon and post-monsoon season correlated positively with the emergence of the recruits in a significant manner. Furthermore, a decline in rainfall during the monsoon period was also recorded which bears a significant positive correlation with the establishment of recruits. However, the increase in the precipitation during winter resulted in a positive effect on the emergence of recruits. The biophysical parameters, like average height, diameter as well as the average age of the dominant trees showed a declining trend with the elevation. However, the age histogram revealed that the majority of the establishment occurred around 1900 and between 1975–2010. The tree ring analysis of J. macropoda revealed that the species is shifting upward at a rate of 3.91 m year−1. Besides this, the area is experiencing the impact of climate change resulting in an increase in the area under vegetation and migration towards the higher elevation, and many species of lichens were also found to invade the bare rock. [ABSTRACT FROM AUTHOR]

Juniperus macropoda is the only tree species of a cold desert ecosystem that is experiencing high anthropogenic pressure and has a poor regeneration status due to harsh environmental conditions. Due to the limited distribution of Juniperus macropoda in this region, the species have remained largely unexplored in terms of understanding the distribution pattern along the elevation and soil fertility gradients. Therefore, the current research was carried out along the elevational gradient, starting from the base line at 3000 m above sea level (m asl) asl with an elevational plot distance of 180 m. The study revealed that the average density of J. macropoda declined gradually from the first elevation range, i.e., 3000–3180 m asl onward, and extended up to the elevation range of 3900–4080 m asl. However, the average seedling and sapling densities were highest at mid-elevation and extended up to an elevation range of 4080–4260 m asl. The J. macropoda population formed a reverse J-shaped structure only up to 3540–3720 m asl. The maximum total biomass and carbon density were recorded in the lowest elevational range, and decreased subsequently. The primary soil nutrients under study decreased sharply along the elevational gradient. Seedling, sapling and tree distributions had a significantly positive relationship (p < 0.05) with available N, P, K, SOC, silt and clay contents and were negatively correlated (p < 0.05) with sand contents. The outcome of the study will form the basis for devising a plan for the management and conservation of J. macropoda forests. [ABSTRACT FROM AUTHOR]

Agroforestry systems (AFS) and practices followed in India are highly diverse due to varied climatic conditions ranging from temperate to humid tropics. The estimated area under AFS in India is 13.75 million ha with the highest concentration being in the states of Uttar Pradesh (1.86 million ha), followed by Maharashtra (1.61 million ha), Rajasthan (1.55 million ha) and Andhra Pradesh (1.17 million ha). There are many forms of agroforestry practice in India ranging from intensified simple systems of monoculture, such as block plantations and boundary planting, to far more diverse and complex systems, such as home gardens. As a result, the biomass production and carbon sequestration potential of AFS are highly variable across different agro-climatic zones of India. Studies pertaining to the assessment of biomass and carbon storage in different agroforestry systems in the Indian sub-continent are scanty and most of these studies have reported region and system specific carbon stocks. However, while biomass and carbon stock data from different AFS at national scale has been scanty hitherto, such information is essential for national accounting, reporting of C sinks and sources, as well as for realizing the benefits of carbon credit to farmers engaged in tree-based production activities. Therefore, the objective of this study was to collate and synthesize the existing information on biomass carbon and SOC stocks associated with agroforestry practices across agro-climatic zones of India. The results revealed considerable variation in biomass and carbon stocks among AFS, as well as between different agro-climatic zones. Higher total biomass (>200 Mg ha−1) was observed in the humid tropics of India which are prevalent in southern and northeastern regions, while lower total biomass (<50 Mg ha−1) was reported from Indo-Gangetic, western and central India. Total biomass carbon varied in the range of 1.84 to 131 Mg ha−1 in the agrihorticulture systems of western and central India and the coffee agroforests of southern peninsular India. Similarly, soil organic carbon (SOC) ranged between 12.26–170.43 Mg ha−1, with the highest SOC in the coffee agroforests of southern India and the lowest in the agrisilviculture systems of western India. The AFS which recorded relatively higher SOC included plantation crop-based practices of southern, eastern and northeastern India, followed by the agrihorticulture and agrisilviculture systems of the northern Himalayas. The meta-analysis indicated that the growth and nature of different agroforestry tree species is the key factor affecting the carbon storage capacity of an agroforestry system. The baseline data obtained across various regions could be useful for devising policies on carbon trading or financing for agroforestry. [ABSTRACT FROM AUTHOR]